JP2012501067A - Process gas delivery in semiconductor process chambers - Google Patents

Abstract

  A method and apparatus for a gas delivery assembly is provided herein. In some embodiments, the gas delivery assembly includes a gas inlet funnel having a first volume and a gas conduit, wherein the gas conduit exits from the gas conduit and the first through the gas conduit. An outlet for facilitating the flow of gas into the volume, wherein the gas conduit has a second volume smaller than the first volume, and a first cross section near the inlet to a second cross section near the outlet. The second cross section is non-circular. In some embodiments, each conduit has a longitudinal axis that intersects the central axis of the gas inlet funnel.

Description

  Embodiments of the present invention generally relate to semiconductor processing equipment, and in particular, to a gas delivery assembly for introducing process gas into a semiconductor process chamber.

  In some semiconductor process chambers, multiple process gases may be delivered to the process chamber through a common gas inlet, for example, a gas injection funnel located on the ceiling of the process chamber. Such semiconductor process chambers may include those used for chemical vapor deposition (CVD) or atomic layer deposition (ALD), in which the process gas at least partially divides a layer. May be used to deposit on the substrate.

The volume of the common gas inlet may be substantially larger than the volume of the gas conduit that supplies process gas to the inlet. As a result, process gas expands rapidly when entering the inlet. This rapid expansion of the process gas can result in cooling of the process gas—an effect known as Joule-Thompson Cooling. Process gases having a low vapor pressure, such as hafnium tetrachloride (HfCl ₄ ), condense as soon as it cools, thus forming particles that can contaminate the inlet or cause a change in the concentration of the process gas.

  Further, alignment of the gas conduit with the central axis of the common gas inlet may cause a rotating gas vortex in the gas inlet and on the substrate. Due to this vortex, for example, the process gas containing the carrier gas and the reaction vapor is separated, and the concentration of the process gas may be varied.

  Therefore, there is a need in the art for a gas delivery assembly that prevents rapid cooling and vortex formation.

  A method and apparatus for a gas delivery assembly is provided herein. In some embodiments, the gas delivery assembly includes a gas inlet funnel having a first volume and a gas conduit, wherein the gas conduit exits from the gas conduit and the first through the gas conduit. An outlet for facilitating the flow of gas into the volume, wherein the gas conduit has a second volume smaller than the first volume, and a first cross section near the inlet to a second cross section near the outlet. The second cross section is non-circular.

  In some embodiments, an apparatus for processing a substrate includes a process chamber having an internal volume and a gas delivery assembly coupled to the process chamber to introduce process gas into the internal volume. . The gas delivery assembly may be the same as described above.

  In some embodiments, a method for processing a substrate is to flow process gas through one or more first volumes and into a second volume that is larger than each first volume. Each first volume has a cross-section that increases from the first cross-section to the second cross-section in the direction of flow along the longitudinal axis, the second cross-section being non-circular Flowing gas and delivering process gas to the substrate via the second volume.

  Thus, the manner in which the above features of the invention are understood in detail, and the more detailed description of the invention, briefly outlined above, may be made with reference to the embodiments. This is illustrated in the accompanying drawings. It should be noted, however, that the attached drawings only illustrate exemplary embodiments of the invention and for this reason should not be considered as limiting the scope of the invention. This is because the present invention can recognize other equally effective embodiments.

FIG. 2 is a schematic cross-sectional view illustrating a process chamber according to some embodiments of the present invention. FIG. 3 is a schematic side view illustrating a gas delivery assembly and gas conduit according to some embodiments of the present invention. FIG. 2 is a schematic side view illustrating a gas conduit according to some embodiments of the present invention. FIG. 3 is a schematic top view illustrating a gas delivery assembly according to some embodiments of the present invention. FIG. 3 is a schematic top view illustrating a gas delivery assembly according to some embodiments of the present invention. FIG. 3 illustrates a method for processing a substrate according to some embodiments of the present invention.

A method and apparatus for a gas delivery assembly is provided herein. In some embodiments, the gas delivery assembly includes a gas inlet funnel having a first volume and one or more gas conduits. Each gas conduit has an inlet and an outlet that facilitates the flow of gas through the gas conduit and into the first volume, each gas conduit having a second smaller than the first volume. In addition, each gas conduit has a cross section that increases from a first cross section near the inlet to a second cross section near the outlet, the second cross section being non-circular. A gas delivery assembly can be coupled to the process chamber to facilitate introduction of process gas into the process chamber. The process gas is flowed in combination with a carrier gas, for example, which may benefit from mitigation of gas separation caused by Joule-Thompson cooling and / or vortex formation, realized by embodiments of the present invention and described below. May include a hafnium precursor such as hafnium tetrachloride (HfCl ₄ ) or other low vapor pressure reaction gases.

  As used herein, “atomic layer deposition” (ALD) or “circular deposition” introduces two or more reactive compounds sequentially to deposit one layer of material on a substrate surface. It means to do. Two, three or more reactive compounds may be alternately introduced into the reaction zone of the processing chamber. Typically, each reactive compound is separated by a time delay so that each compound can adhere to and / or react on the substrate surface. In one aspect, a first precursor, such as a hafnium precursor, or Compound A is pulsed into the reaction zone, followed by a first time delay. Next, a second precursor, such as an oxidizing gas, or Compound B is pulsed into the reaction zone, followed by a second delay. The oxidizing gas may include several oxidizing chemicals such as in-situ water and oxygen. During each time delay, a purge gas such as nitrogen is introduced into the processing chamber to purge the reaction zone or otherwise remove any residual reactive compounds or byproducts from the reaction zone. Alternatively, the purge gas may flow continuously throughout the deposition process so that only the purge gas flows during the time delay between pulses of reactive compound. The reactive compound is alternately pulsed until the desired film or film thickness is formed on the substrate surface. In any scenario, the compound “A” pulse, purge gas, compound B pulse, or purge gas ALD process is a cycle. The cycle begins with either Compound A or Compound B and continues through each sequence of cycles until a desired thickness of film is achieved.

  FIG. 1 is a schematic cross-sectional view of a process chamber 100 according to some embodiments of the present invention. The process chamber 100 includes a gas delivery assembly 130 that is adapted for cyclic deposition, such as atomic layer deposition (ALD) or rapid chemical vapor deposition (rapid CVD). The terms ALD and fast CVD, as used herein, refer to the continuous introduction of reactants to deposit a thin layer on the substrate. The continuous introduction of reactants may be repeated to deposit multiple thin layers to form a conformal layer of the desired thickness.

  Process chamber 100 includes a chamber body 104 having a sidewall 110 and a bottom 106. A slit valve 102 in the process chamber 100 allows a robot (not shown) to access the substrate 112 in and out of the process chamber 100. In some embodiments of the present invention, the substrate 112 may be a semiconductor wafer or glass substrate having a diameter of 200 mm or 300 mm. Process chamber 100 may include any suitable chamber configured for ALD or high-speed CVD that may benefit from the inventive apparatus and method disclosed herein. Some exemplary process chambers are U.S. patents filed May 12, 2005 and assigned to the assignee of the present invention entitled "Apparatuses and Methods for Atomic Layer Deposition of Hafnium-Containing High-K Dielectric Materials". And published in US Patent Application Publication No. 2005-0271813 and US Patent Application Publication No. 2003-0079686, filed December 21, 2001, entitled "Gas Delivery Apparatus and Method for Atomic Layer Deposition" The application is hereby incorporated by reference in its entirety. Two exemplary chambers suitable for practicing at least a portion of the inventive techniques include Applied Materials Inc. There may be GEMINI ALD or CVD available from.

  The substrate support 108 supports the substrate 112 on the substrate receiving surface 191 in the process chamber 100. The substrate support (or pedestal) 108 is attached to a lift motor 114 so as to raise and lower the substrate support 108 and the substrate 112 disposed thereon. A lift plate 116 connected to a lift motor 118 is mounted in the process chamber 100 and raises and lowers pins 120 arranged to move through the substrate support 108. The pins 120 raise and lower the substrate 112 over the surface of the substrate support 108. In some embodiments of the present invention, the substrate support 108 may include a vacuum chuck, electrostatic chuck, or clamping ring that secures the substrate 112 to the substrate support 108 during processing.

  The substrate support 108 may be heated to increase the temperature of the substrate 112 disposed thereon. For example, the substrate support 108 may be heated using an embedded heating element such as a resistance heater, or heated using radiant heat such as a heating lamp disposed on the substrate support 108. Sometimes. A purge ring 122 may be disposed on the substrate support 108 to define a purge channel 124 that supplies a purge gas to the periphery of the substrate 112 to prevent deposition on the periphery of the substrate 112.

  The gas delivery assembly 130 is disposed on top of the chamber body 104 to supply a gas, such as process gas and / or purge gas, to the process chamber 100. For example, in some embodiments, the process gas may include a hafnium precursor or other suitable reaction gas and carrier gas with low vapor pressure. A vacuum system 178 communicates with the pumping channel 179 to evacuate any desired gas from the process chamber 100 and further maintain the interior of the pumping zone 166 of the process chamber 100 at a desired pressure or a desired pressure range. help.

  The gas delivery assembly 130 may further include a chamber lid 132. The chamber lid 132 may include a gas inlet funnel 134 that extends from the center of the chamber lid 132 and a bottom surface 160 that extends from the gas inlet funnel 134 to the periphery of the chamber lid 132. The bottom surface 160 is sized and shaped to substantially cover the substrate 112 disposed on the substrate support 108. The chamber lid 132 may have a choke 162 on the periphery of the chamber lid 132 adjacent to the periphery of the substrate 112. The cap portion 172 includes a part of the gas inlet funnel 134 and gas inlets 136A, 136B, 136C, and 136D. The gas inlet funnel 134 has gas inlets 136A, 136B, 136C, 136D that supply gas flows from two similar valves 142A, 142B, 142C, 142D. Gas flows from valves 142A, 142B, 142C, 142D may be supplied together and / or separately.

An embodiment of a gas inlet assembly that can facilitate mitigation of gas separation caused by Joule-Thompson cooling and vortex formation is described below with respect to FIGS. 2A-B and 3A-B. In general, such embodiments relate to the cross-sectional shape of one or more gas conduits 150 and the orientation of those conduits relative to the gas inlet funnel 134.

  2A-B depict a three-dimensional view of a portion of a gas delivery assembly 130 that includes a gas inlet funnel 134 and one or more gas conduits 150 according to some embodiments of the present invention. Referring to FIG. 1, gas conduits 150A, 150B, 150C, and 150D are disposed between gas inlets 136A, 136B, 136C, 136D and valves 142A, 142B, 142C, 142D.

  The gas inlet funnel 134 depicted in FIG. 2A is generally cylindrical in shape and may have a first volume and a central axis disposed through the gas inlet funnel 134. In some embodiments, such as those depicted in FIG. 1, the gas inlet funnel 134 may have a cross section that expands in the direction of gas flow along at least a portion of the central axis. The gas inlet funnel 134 may comprise one or more tapered internal surfaces (not shown), such as a tapered straight surface, a concave surface, a convex surface, or combinations thereof, or one Or it may comprise a plurality of tapered internal surface sections (ie, tapered and non-tapered portions).

  Gas conduits 150A, 150B, 150C, and 150D are coupled to gas inlet funnel 134 at gas inlets 136A, 136B, 136C, and 136D, respectively. As illustrated in FIG. 2B, each gas conduit passes through the conduit along the longitudinal axis and through each gas inlet 136 into a first volume defined by the gas inlet funnel 134. And an outlet 152 that facilitates the flow of process gas. Each gas conduit 150 defines a second volume that is smaller than the first volume of the gas inlet funnel 134. The difference between the first volume and the second volume is that the process gas flowing from the second volume of the gas conduit 150 into the first volume of the gas inlet funnel in the absence of the present invention experiences a Joule-Thompson cooling effect. In some cases, the Joule-Thompson cooling effect can cause the formation of fine particles from the process gas and variations in the concentration of the process gas delivered to the substrate.

  To mitigate Joule-Thompson cooling, each gas conduit 150 may be shaped to have a cross section that increases from a first cross section near inlet 151 to a non-circular second cross section near outlet 152. . A cross section that increases along the direction of gas flow between the inlet 151 and the outlet 152 gradually increases the volume of the gas conduit, thereby maintaining, for example, the chemical equilibrium of the low vapor pressure reactant gas. Thus, a gradual enlargement of the cross section of each gas conduit 150 can reduce the rapid temperature drop of the reaction gas. In some embodiments, as a non-limiting example, the first cross section near the inlet 151 may be circular. However, any suitable shape can be chosen for the first cross section.

  The second cross section near the outlet 152 of each gas conduit 150 may be non-circular. As depicted in FIG. 2B, the second cross section may be generally rectangular. However, other suitable shapes may be considered. In some embodiments, the ratio of the area of the first cross section to the area of the second cross section is about 3: 1 or greater. One of ordinary skill in the art may use other ratios to successfully handle the process gas temperature drop caused by Joule-Thompson cooling along each gas conduit in the enlarged cross section between inlet 151 and outlet 152. .

  In some embodiments, a non-circular shape is chosen for the second cross-section to maximize the surface area of the gas conduit that the process gas flowing through the gas conduit contacts. For example, in some embodiments where an external heater is coupled to the external surface of each gas conduit, such a non-circular shape that maximizes surface area may be chosen. The external heater can supply heat as a further means of mitigating Joule-Thompson cooling caused by the enlarged cross-section of each gas conduit between the inlet 151 and outlet 152. The maximized surface area of the second cross section in contact with the heater can facilitate maximum heat transfer along the second cross section.

  Returning to FIG. 2A, in some embodiments, each gas conduit 150 has a longitudinal axis 152 that intersects the central axis 154 of the gas inlet funnel 134. Such an orientation can achieve laminar flow of process gas within the gas inlet funnel 134, thus reducing vortex formation. Further, laminar flow in the gas inlet funnel 134 can improve purging of the inner surface of the gas inlet funnel 134 and other surfaces of the chamber lid 132.

  Further, as a non-limiting example, each gas conduit 150 has a longitudinal axis perpendicular to the central axis of the gas inlet funnel 134, such as that depicted in FIG. 2A for gas conduits 150A, 150B, 150C, and 150D. Can have. However, the one or more gas conduits 150 may be oriented at an angle with respect to the central axis of the gas inlet funnel 134 if desired.

  In some embodiments, at least two conduits may have fully opposed longitudinal axes 152. For example, as depicted in FIG. 2A, gas conduits 150A, 150B and gas conduits 150C, 150D have fully opposed longitudinal axes 152. The fully opposed longitudinal axes intersect the central axis of the gas inlet funnel 134 as illustrated in the top view of FIG. 3A.

  Other configurations of the gas conduit 150 are possible. In some embodiments, as depicted in the top view of FIG. 3B, at least two gas conduits, such as gas conduits 150A, 150B, have a vertical longitudinal axis that intersects the central axis 154 of the gas inlet funnel 134. 156, 158. One skilled in the art can utilize one or more oriented gas conduits 150A, 150B, 150C, 150D along the gas inlet funnel 134 as described above.

  Returning to FIG. 1, in some embodiments, valves 142A, 142B, 142C, and 142D are coupled to separate reactive gas sources, but are preferably coupled to the same purge gas source. For example, valve 142A is coupled to reactive gas source 138A, valve 142B is coupled to reactive gas source 138B, and both valves 142A, 142B are coupled to purge gas source 140. Each valve 142A, 142B, 142C, 142D includes a delivery line 143A, 143B, 143C, and 143D. The delivery lines 143A, 143B, 143C, 143D communicate with the reactive gas sources 138A, 138B, 138C, 138D, and further through the gas conduits 150A, 150B, 150C, 150D, the gas inlets 136A, 136B, 136C, It is in communication with 136D. In some embodiments, additional reactive gas sources, delivery lines, gas inlets and valves may be added to the gas delivery assembly 130. Purge lines such as 145A, 145B, 145C, and 145D are in communication with the purge gas source 140, and the flow of the purge lines 145A, 145B, 145C, and 145D is controlled by valves 146A, 146B, 146C, and 146D, respectively. The Purge lines 145A, 145B, 145C, and 145D intersect delivery lines 143A, 143B, 143C, and 143D at valves 142A, 142B, 142C, and 142D. When a carrier gas is used to pump the reactant gas from the reactant gas sources 138A, 138B, 138C, 138D, in one embodiment, the same gas is used as the carrier gas and purge gas (eg, nitrogen is the carrier gas and purge gas). Used as). Valves 142A, 142B, 142C, and 142D include a diaphragm. In some embodiments, the diaphragms can each be offset open or closed and can be moved to close or open. The diaphragm can be moved pneumatically or can be moved electrically. An example of a pneumatically actuated valve is a pneumatically actuated valve available from Swagelock, Solon, Ohio. A pneumatically actuated valve can supply a pulse of gas for a time on the order of about 0.020 seconds. The electrically actuated valve can supply a pulse of gas for a time on the order of about 0.005 seconds. Electrically actuated valves typically require the use of a driver coupled between the valve and a programmable logic controller such as 148A, 148B.

  Each valve 142A, 142B, 142C, 142D may be adapted to provide a combined gas flow and / or individual gas flow of the reaction gases 138A, 138B, 138C, 138D and the purge gas 140. With respect to valve 142A, one example of a combined gas flow of reaction gas 138A and purge gas 140 supplied by valve 142A includes a continuous flow of purge gas from purge gas source 140 through purge line 145A and a delivery line 143A. It includes a pulsed reaction gas from a source of reactive gas 138A.

  Delivery lines 143A, 143B, 143C, and 143D of valves 142A, 142B, 142C, and 142D are coupled to gas inlets 136A, 136B, 136C, and 136D through gas conduits 150A, 150B, 150C, and 150D. . Gas conduits 150A, 150B, 150C, and 150D may be integrated into valves 142A, 142B, 142C, and 142D, or may be separate. In one embodiment, valves 142A, 142B, 142C, and 142D include gas conduits 150A between delivery lines 143A, 143B, 143C, 143D and valves 142A, 142B, 142C, 142D and gas inlets 136A, 136B, 136C, 136D. , 150B, 150C, 150D are coupled in close proximity to the gas inlet funnel 134 to reduce any unnecessary volume.

  The gas inlets 136A, 136B, 136C, 136D are positioned adjacent to the upper portion 137 of the gas inlet funnel 134. In other embodiments, one or more gas inlets 136A, 136B, 136C, 136D may be positioned along the length of the gas inlet funnel 134 between the upper portion 137 and the lower portion 135.

  At least a portion of the bottom surface 160 of the chamber lid 132 provides an improved velocity distribution of gas flow from the gas inlet funnel 134 over the entire surface of the substrate 112 (ie, from the center of the substrate 112 to the edge of the substrate 112). May be tapered from the gas inlet funnel 134 to the periphery of the chamber lid 132. In some embodiments, the bottom surface 160 may include one or more tapered surfaces, such as a straight surface, a concave surface, a convex surface, or combinations thereof. In some embodiments, the bottom surface 160 is tapered in the form of a funnel.

  A control unit 180, such as a programmed personal computer, workstation computer, or the like, may be coupled to the process chamber 100 to control processing conditions. For example, the control unit 180 may control the various sources from the gas sources 138A, 138B, 138C, 138D, 140 by valves 142A, 142B, 142C, 142D, 146A, 146B, 146C, 146D at various stages of the substrate process sequence. It may be configured to control the flow of process gas and purge gas. Illustratively, the control unit 180 includes a memory 186 that includes a central processing unit (CPU) 182, support circuitry 184, and associated control software 183. The control unit 180 can directly control each component of the process chamber 100, which is illustrated by a plurality of control lines 188 that couple the control unit 180 to each chamber component. Alternatively, the control unit 180 may be coupled to and control individual control units (not shown) of each chamber system. For example, the control unit 180 may be coupled to individual control units (not shown) of the gas delivery assembly 130, in which case the individual control units of the gas delivery assembly 130 may be coupled to the gas delivery assembly 130. Each component of the item 130, for example, the gas sources 138A-D is controlled.

FIG. 4 illustrates a method of processing a substrate 112 according to some embodiments of the present invention. The processing may include, for example, depositing a hafnium oxide (HfO _x ) film on the substrate by an ALD process. The deposition process generally removes hafnium precursors that are subject to Joule-Thompson cooling when rapidly expanding in volume or may be separated from the carrier gas as a result of vortex formation when entering the gas inlet funnel, generally nitrogen (N ₂ ) in combination with a carrier gas. Accordingly, the gas conduit 150 and gas inlet funnel 134 embodiments described above may be advantageously utilized with the method 400 to prevent the occurrence of such undesirable effects.

  The method 400 is described in connection with the process chamber 100 depicted in FIG. In step 402, the substrate 112 is loaded into the process chamber 100.

  At step 404, gas is flowed through the one or more first volumes (ie, gas conduit 150) and into the second volume (ie, gas inlet funnel 134). In some embodiments, hafnium precursor is flowed through one gas conduit 150 and oxygen-containing precursor is flowed through another gas conduit 150. The hafnium precursor and the oxygen-containing precursor can be pulsed separately or simultaneously in an ALD process to form a hafnium oxide film on the substrate 112.

  The gas inlet funnel 134 and the gas conduit 150 can be arranged in any suitable arrangement as described above. At a minimum, as described above, each gas conduit 150 has a longitudinal axis that intersects the central axis of the gas inlet funnel 134. Advantageously, this orientation can prevent vortex formation as the gas exits the gas conduit 150 and flows into the gas inlet funnel 134. Further, as stated above, each gas conduit 150 has a cross-section that, at a minimum, increases from the first cross-section along the longitudinal axis from the first cross-section, the second cross-section being non-circular. It is. This geometry of the gas conduit, as mentioned above, advantageously reduces Joule-Thompson cooling and provides more surface area for heat transfer.

  In some embodiments, the temperature drops along gas conduits 150A, 150B, 150C, and 150D as gas (eg, hafnium precursor and carrier gas) flows through each gas conduit. Unlike the large temperature drop from about 200 degrees Celsius to 108 degrees Celsius in the conventional design, the temperature drops only slightly from about 190 degrees Celsius to about 183 degrees Celsius. A conventional design may be, for example, a gas conduit having a rapidly expanding cross section. Maintaining the temperature of each gas conduit 150 above about 180 degrees Celsius helps to keep the hafnium precursor in vapor form. In some embodiments, as described above, a heater may be coupled to each gas conduit 150 and utilized to further reduce the temperature drop of the process gas flowing through each gas conduit 150.

At step 406, gas is pumped through the second volume (ie, gas inlet funnel 134) to the substrate 112. In some embodiments, hafnium precursor is introduced into the process chamber 100 through the gas conduit 150 and the gas inlet funnel 134 at a rate from about 5 mg / m to about 200 mg / m. The hafnium precursor is usually introduced with a carrier gas such as nitrogen and the total flow rate is in the range of about 50 sccm to about 2,000 sccm. In a conventional ALD process, hafnium precursor is pulsed into the process chamber 100 with a duration of about 1 second to about 10 seconds, depending on the particular process and the desired hafnium-containing compound. In highly advanced ALD processes, the hafnium precursor is pulsed into the process chamber 100 with a shorter duration from about 50 ms to about 3 seconds. In some embodiments, the hafnium precursor may be hafnium tetrachloride (HfCl ₄ ). In some embodiments, the hafnium precursor may be tetracas (diethylamine) hafnium ((Et ₂ N) ₄ Hf or TDEAH).

  The oxygen-containing precursor is introduced into the process chamber 100 at a rate in the range of about 10 seem to about 1,000 seem, preferably in the range of about 30 seem to about 200 seem. In conventional ALD processes, the oxidizing gas is pulsed into the process chamber at a rate from about 0.1 seconds to about 10 seconds, depending on the particular process and the desired hafnium-containing compound. In highly advanced ALD processes, the oxidizing gas is pulsed into the process chamber with a shorter duration from about 50 ms to about 3 seconds.

  The substrate 112 is then exposed to a pulse of hafnium precursor introduced into the process chamber 100 for a time in the range of about 0.1 seconds to about 5 seconds. Next, a pulse of oxygen-containing precursor is introduced into the processing chamber 100. In some embodiments, the oxygen-containing precursor may include some oxidizing chemicals such as in situ water and oxygen. Suitable carrier or purge gases may include helium, argon, nitrogen, hydrogen, forming gas, oxygen and combinations thereof. “Pulse” as used herein is intended to mean an amount of a particular compound introduced intermittently or discontinuously into the reaction zone of the processing chamber 100.

  After each deposition cycle, a specific thickness of hafnium-containing compound, such as hafnium oxide, is deposited on the surface of the substrate 112. In some embodiments, each deposition cycle forms a layer having a thickness in the range of about 1-10 angstroms. Depending on the specific device requirements, the subsequent deposition process may be required to deposit a hafnium-containing compound having a desired thickness. As such, the deposition process is repeated until the desired thickness of the hafnium-containing compound is achieved. Thereafter, the process is stopped when the desired thickness is achieved.

Hafnium oxide deposited by the ALD process has the empirical chemical formula HfO _X. Hafnium oxide has the molecular chemical formula HfO ₂ , but by changing process conditions (eg, time regulation, temperature, precursor), hafnium oxide is not fully oxidized, eg, HfO _1.8+. Sometimes. Preferably, hafnium oxide is deposited with a molecular chemical formula of about HfO ₂ or less by the process herein.

  In some embodiments, the cyclic deposition process or ALD process of FIG. 1 is in the range of about 1 Torr to about 100 Torr, preferably in the range of about 1 Torr to about 20 Torr, such as about 1 Torr to about 10 Torr. At a pressure of. In some embodiments, the temperature of the substrate 112 is typically about 70 degrees Celsius to about 1,000 degrees Celsius, preferably about 100 degrees Celsius to about 650 degrees Celsius, more preferably about 250 degrees Celsius to about 500 degrees Celsius. It is a range of degrees.

The hafnium precursor is typically dispensed into the process chamber 100 by introducing a carrier gas into a bubbler containing the hafnium precursor. Suitable bubblers, such as PROE-VAP®, are available from Advanced Technology Materials Inc. in Danbury, CT. Can be obtained from The temperature of the bubbler is maintained at a temperature depending on the internal hafnium precursor, such as a temperature of about 100 degrees Celsius to about 300 degrees Celsius. For example, the bubbler may include HfCl ₄ at a temperature from about 150 degrees Celsius to about 200 degrees Celsius.

In some embodiments, the oxidizing gas is generated in a water vapor generator (WVG) system that is in fluid communication with the process chamber 100 in one line. The WVG system generates ultra-high purity water vapor by the catalytic reaction of O ₂ and H ₂ . Unlike high temperature generators that produce water vapor as a result of combustion, the WVG system has a reactor or catalyst cartridge lined with a catalyst in which water vapor is generated by a chemical reaction. By adjusting the flow of H ₂ and O ₂ , the concentration can be accurately controlled at any point from 1% to 100% concentration. Water vapor, may contain _water, H 2, _{O 2,} and combinations thereof. Suitable WVG systems are commercially available, for example, Fujikin of America Inc. in Santa Clara, California. For example, and WGS by CLS (Catalyst Steam Generator System) by Ultra Clean Technology in Menlo Park, California.

  A pulsed purge gas, preferably argon or nitrogen, is introduced at a rate from about 1 slm to about 20 slm, preferably from about 2 slm to about 6 slm. Each treatment cycle lasts from about 0.01 seconds to about 20 seconds. For example, in some embodiments, the processing cycle is about 10 seconds, while in some other embodiments, the processing cycle is about 2 seconds. Longer processing steps lasting about 10 seconds deposit excellent hafnium-containing films, but reduce throughput. Specific pressures and times are obtained by experiment.

  Many precursors are within the scope of the present invention. One important precursor feature is that it has a favorable vapor pressure. The precursor may be a gas, liquid or solid at ambient temperature and pressure. However, vaporized precursors are utilized in the ALD chamber. Organometallic compounds or composites include any chemical containing metal and at least one organic group such as amide, alkyl, alkoxyl, alkylamide and anilide. Precursors may include organometallic compounds, inorganic compounds and halogenated compounds.

An exemplary ALD process is a hafnium oxide film grown by continuously pulsing a hafnium precursor with in situ vapor formed in a water generator. The substrate surface is exposed to a pretreatment to form hydroxyl groups. The hafnium precursor HfCl ₄ is maintained at a temperature of about 150-200 degrees Celsius in the precursor bubbler. A carrier gas such as nitrogen is fed into the bubbler at a flow rate of about 400 sccm. The hafnium precursor saturates the carrier gas and is pulsed into the chamber for 3 seconds. A nitrogen purge gas is pulsed into the chamber 100 for 3 seconds to remove any unbound hafnium precursor. Hydrogen gas and oxygen gas are supplied to the water vapor generator (WVG) system at flow rates of 120 sccm and 60 sccm, respectively. In situ steam leaves the WVG with approximately 60 sccm of water vapor. In situ vapor is pulsed into the chamber for 1.7 seconds. The nitrogen purge gas is pulsed into the chamber 100 for 4 seconds to allow any unbound or unreacted reagents such as by-products, hafnium precursors, oxygen and / or water or any by-products such as HCl. And so on. The temperature of the substrate 112 is maintained at a temperature of about 400 to 600 degrees Celsius. Illustratively, each ALD cycle may form a hafnium oxide film of about 0.8 angstroms.

Embodiments of the present invention have been described as depositing hafnium-containing compounds, but by alternately pulsing metal precursors with oxidizing gases such as water vapor and O ₂ fluids obtained from WVG systems. In addition to the hafnium-containing compound, various metal oxides and / or metal silicates can be formed. By using other metal precursors instead of hafnium and / or silicon precursors, the ALD process disclosed above can be altered to produce hafnium aluminate, titanium silicate, zirconium oxide, zirconium silicate, zirconium aluminate, oxidation Materials such as tantalum, tantalum silicate, titanium oxide, titanium silicate, silicon oxide, aluminum oxide, aluminum silicate, lanthanum oxide, lanthanum silicate, lanthanum aluminate, nitrides thereof, and combinations thereof can be formed.

  A method and apparatus for a gas delivery assembly is provided herein. The gas delivery assembly can advantageously achieve reduced Joule-Thompson cooling by a gas conduit having an enlarged non-circular cross section that is optionally coupled to an external heater. By orienting the gas conduits such that the longitudinal axis of each conduit intersects the central axis of the gas inlet funnel, vortex formation in the gas inlet funnel can be advantageously reduced.

  While the foregoing is directed to embodiments of the invention, other and further embodiments of the invention may be devised without departing from the basic scope thereof.

Claims (15)

A gas inlet funnel having a first volume;
A gas conduit;
The gas conduit has an inlet for receiving gas and an outlet for facilitating the flow of the gas out of the gas conduit and into the first volume, the gas conduit being the first A second volume that is smaller than the volume, and a cross section that increases from a first cross section near the inlet to a second cross section near the outlet, the second cross section being non-circular;
Gas delivery assembly.   The gas delivery assembly of claim 1, wherein the gas conduit has a longitudinal axis that intersects a central axis of the gas inlet funnel.   The gas delivery assembly of claim 2, further comprising two gas conduits, the two gas conduits having completely opposite longitudinal axes.   The gas delivery assembly of claim 1 or 2, further comprising two gas conduits, the two gas conduits having longitudinal axes that intersect at right angles.   A gas delivery assembly according to any preceding claim, wherein each gas conduit has a longitudinal axis perpendicular to the central axis of the gas inlet funnel.   A gas delivery assembly according to any preceding claim, wherein each gas conduit has a longitudinal axis arranged at an angle with respect to the central axis of the gas inlet funnel.   7. A gas delivery assembly according to any preceding claim, further comprising a heater coupled to each gas conduit to heat the gas flowing through the conduit.   8. A gas delivery assembly according to any preceding claim, wherein the gas inlet funnel has a cross section that increases in the direction of gas flow along at least a portion of the central axis.   9. A gas delivery assembly according to any preceding claim, wherein the ratio of the cross-sectional area of the outlet to the inlet of each gas conduit is about 3: 1 or greater. An apparatus for processing a substrate,
A process chamber having an internal volume;
An apparatus comprising: a gas delivery assembly according to any preceding claim, coupled to the process chamber to introduce process gas into the interior volume. A method for processing a substrate, comprising:
Flowing process gas through one or more first volumes into a second volume larger than each of the first volumes, each first volume flowing along a longitudinal axis; Flowing a process gas having a cross-section that increases from a first cross-section to a second cross-section in the direction of, wherein the second cross-section is non-circular;
Delivering the process gas to the substrate via the second volume.   The method of claim 11, wherein the longitudinal axis of each first volume is aligned with a central axis of the second volume.   13. A method according to any of claims 11 to 12, further comprising flowing the process gas from at least two first volumes, wherein the at least two first volumes have completely opposite longitudinal axes. .   13. A method according to any of claims 11 to 12, further comprising flowing the process gas from at least two first volumes, wherein the at least two first volumes have longitudinal axes intersecting at right angles.   15. A method according to any of claims 11 to 14, further comprising heating the process gas that is flowed into each first volume.

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